Device for testing insulators carrying live wires



Nov. l, 1927.

L. P. DEI-SASSO ET AL DEVICE FOR TESTING INSULATORS CARRYING LIVE WIRES Filed May 9, v1922 2 nSmets-sheet 1 yad.

am, ,w d E Nov. l, 192 7.

Y L.. P. DELSASSO E1"y AL DEVICE FO TESTING INSULATORS CARRYING LIVE WIRES Filed May 9, 1922 2 Sheets-Sheet 2 .a a a l W.. vf w Patented Nov. 1,' 1927.

UNITED STATES* PATENT o `Lne fr. DnLsAsso. BENJAMIN n. DENGLER, AND `rms/'IN a.

` ANGELES, cALIJzozaNIA.Y

FFIC. Y

S'IAnrrncnnia, orfLos p `DEvIGn 4non TESTING INsULA'roRs CARRYING LIvE WIRES.

`Application filed May 9,1922. i Serial No. 559,518.

object of the present invention is to provide a device by which the insulators ymay be easilywand quickly tested, while the line is energized, Without any danger to the person -maltilngthe test, and without the necessity of shortcircuiting the insulator under test.

- `.To this-'end our invention comprises an electrostaticvolt meter of suitable sensitivel "ness, arranged in combination withacarry-` ing' member (preferably 4a long pole) and a` pair otcontact" rodsthat may be placed in Contact with opposite sidesor endsfof the insulator.y `When the device is put into operative 1 position, ifan insulator is in good operating' `condition,that `fact is inmuedi-l ately` visually shown by abnormal movement of the'.statically charged part ot the device. Ifthelinsulator should be defective no .suc

movement results.

There are several otherffeatures in our yin- `venti-on, accomplishing corresponding obf the indicator device 11, `.and the pair of con-l fjects,alllotwhicln however, will be best .un-

derstood from detailed ydescriptions of typir` `be apparentwhe'n the `action` ofthe device is cal` forms of devices embodying the invention. f For this purpose reference is had .to -f thefalccompanying drawings. p 35` i Figfl `is aside elevation of one form of ourtdevice; Fig. 2 is another side elevation i ot'l thesame; Fig. `3 is an enlarged longitudinal section of the indicatorfpartof the de vice; Fig. #l is a section taken as indicated byline .4C-Ji on 31; Fig. lis a cross sec-"yy 'tiontalren as indicated by linee-f5 on Figs. 3 and'AqFig. bis aside elevation of another torniof the deviceyFig. 7 is anotherside elevation of the same; Fig. Sis an enlarged longitudinal section of the-indicator parts of this' `term of device,V Fig.. 9 is a section talren 'asindicated by line k9--19 on Fig. 8; and Fig. 10 is a plan yoli the parts yshown In "Describing first more the detailsmoiithe form shownfin Figs. l to '5, yit "will `beseen that there'are used alongpole orotlier suitable carrier 10,wh1ch carrles :tact rods l2. The contact rods are prefere ably arranged or made so that they may be adjusted, as to the distance rr between their" two ends; this may be done by making the"L f i" contact rodsflexible in any suitable manner.

For instance these rods may be pivotally ,adjustable at 13 to adjust the distance between their two ends to suit the lineardistancebetweenopposite terminals ot ian in` sulator.. When'we speakof terminalsof` an 'insulator we mean those parts between which there is a potential dili'erence; as the two hardware. httings of `a high tension insu.-

yshown as mountediupon 'al T-headot insu.-

` later; or .th-e top of an .ordinarypetticoat,-

lating material ltonthev end of polelOg 'y and theindicator llis shown as Vmounted onlthepole Vclose vto `the kT-heasd. The pole and head 14 may be made otiany suitable yinsulating lmaterial. VTheipol-e is `of sutli-y cient length toguarantee the :safety -`of the' lineman lwhile making tests. The indicator device of the' spaced membersat fleastfoneof which" is connected to .the two Contact rodslQk so as to be opposltely charged.V Although, as will form here `shown comprises Lprimarily two changeable' 80 i understood, a .single movable Vreed is sulli'- cient-to giye the indications desired, fa pair vof reeds with a 4suitable pair of platesgives" Y i a better visual indication. Accordingly, in

the form lot deviceashown *in vthese figures, r there 1s a'pair of movable reeds 20,1nounted l inside A a rectangular `tubef21 kof `insulating material; and onl Vopposite faces ol1 :theeX-xi .i

terior ofthe tube, andoplposite thetwo reeds,

there k@are two nietallicplatesl. -Tliiswhole arrangement isy surrounded by a sheathing or in Figf. Projections 24(also` preferably of fibre or the like ion. the rectangular tubeQl i extend through thelplates 22 and the `fibre tween the `free ends .of the fibre sheath there (is a .block `fand a .set screw 26 (which works ina vnut l27 set inblock 25) r maybe set `sheath 23 :to hold the parts inplace. 5Bedown against the :pole i 10`to holdthefindicator ll inlanydesired.positionvaround the pole. When the device is being used the indicator Yis turned to such a position on the pole, that the lreeds 2O remain substantiallyV 'f- Reeds 20 are mounted upon a metal-block 30 which closes one end of tube 21 (the end adjacent to Vthe metal prongs 12),. TheV two reeds are mounted on 'pivoted anglepieces 35, pivoted at 36; and screws' 37 serve to adjust the position of thesef anglepieces 85 and thus serve to adjust the normal position of the reeds 20. The tree ends ofthe reeds may extend ap proximately to the openend oftube 21.; ando "those yi'ree ends have laterally turned-parts 38 whose comparatively broad surfaces, as viewed endwise through the open end of tube 2l, enable the reeds to be distinctly seen by the tester. These'reeds are, in a typical device, made of thinaluminum (approximately siX tlious'andths of an inch thick).

The. mere `end edge'otl such a pieceis not easily visible. The broad surface afforded by the laterally turned is'easily visible. f

The two'plates 22 areconnected hyd-wire et() to one'of the'contact: rods12, while a wire 111 connectsy the other contact rodl with' a plate. ft2 and hence tothe reeds20. This Aplate a2 also overliefs ianges 37a onv the screw 3 heads so that the screws arelongitudinally immovable with reference to blockBO. When the device is being lused the distance between the ends 'of rods `12 is adjusted to suit the size of the insulatorbeingtested, and the rods are then put in contact'withthe itwo terminals of the insulator. Or, in -test-iiig suspension type insulators, these contact rods are put into contact with theterm'inals of the particular insulator under test. "Theindicator device 5111., is vadjusted vso that it hangs down "on the pole 10, or it free-to swing, ytakes the'. vertical 'position Under these conditionsvthe reedsJrwill giveva-v proper plates l22and reeds 20 arefoppositely electro-4 statically charged; and'thisopposite electroing the reeds L aart.' TheY sensitiveness'f'of the instrument' epends yof course upon they distance between ther reeds andthe plates 22, Aupon the thickness of thedielectric wall 21, and thelength, crosssectional area, and' elasticity of the reeds 20. Thesefactors may parts at 38., however,

"easily visible divergence between the reeds when the difference in potential-between opposite terminals of an insulator is up to normal. If an insulator has broken down, however, then the difference in potential between opposite terminals become less and the reeds will then shown little or no divergence. This divergence is very easily noted by the lineman making the test; particularly because the surfaces at the ends of the reeds are readily seen. The inclosing tube 21 may be made ot black bakelite or some similar materialrand the material of the reeds, in this case aluminum, is such that the visual surfaces atz38 reflect enough light to be readily seen inthe dark enclosure and their movements easily detected.

It will now be readily understood that one plate '22 and one reed 20 will operate to give the desired indication; but the double arrangement, including the two reeds that move in op iosite directions, give a more distinctive inc ication, yand one that is more `readily seen by the lineman, patrolman, or

other individual making the test.

In t-he 'form' shown invFigs. 6 to 10 the vgeneral :arrangement is the same as before described, but the indicator device 11 is slightly modified. Here we utilize a pair of reeds 2OrL turned at their ends as indicated at 38a andinounted at their inner ends on mounting members 50 that may be sprung awayffrom the central dielectric slab 51 by `theoperationof suitable screws 52. Thus screws 52 serve to adjust the normal posivtionsot reeds`20. The wire 41 connects the vand Vthis box may have projections 24 that I l serve to keep ytheboi; -roni slipping longiindication of any defective insulator.' 'The tudinally in the encircling bands 23a. These bands are preferablyy of fibre or some other at their ends they pass around the pole 10 andare secured together by bolts GO. Blocks preferably olf' an insulating material as shown at 61, maybe placed between the pole 10 andv the box 21.

The operation of this last described form of device is substantially the same as the one previously described, except that the move- 4ment, of ythe reeds, when electrostatically charged, is toward each yother instead of awa-y from'eachother.

j Y suitable insulating or dielectric material, and Y static charge hasthe eitectof attracting the.` reedstowards the plateszresulting in spreade,

lill' of a suspension unit). The .device is sutticiently sensitive to detect any defective in sulator, even Whensuch an insulator is on a dry cross-arm, and Without having to make a metallic short circuit between the opposite terminals -or the opposite yhardware fittings of the insulator, or Without having to ground either'side of the insulator.` For all these reasons, the danger of flashovers on insulators at the time of testing is reduced to a f minimum. In our testing device no metallic circuit whatever 1s form-ed between opposite terminals of the insulators, and there is no appreciable passage of current through the testing device; the action of the testing .de-

vicebeing entirely electrostatic.`

Having described a preferred form of our invention, We claim:

l. An'insulator tester embodying a carriver,y a. pair of spaced contacts thereon adapted to be touched to opposite terminals of an insulator, and a static potential indicator mounted on the carrier and comprising a.

pair of movable reeds and a pair of plates outside the reeds and each in opposition to one of the reeds, the reeds being connected to one Contact and the plates to theother. y

2. In an insulator tester, an enclosure, an

angle bracket pivot-ally mounted at its angle u in the enclosure, one arm of the bracket eX- tending longitudinally of the enclosure and the other transverselythereof, an adjusting screw engaging the transverse arm, and a chargeable reed carried by the longitudinally extending arm. A

In Witness that We claim the :foregoing We have'hereunto subscribed our names this irst day ofMay, 1922.

[Leo P. nnLsAsso.

BENJAMIN r. DENGLER.

u EDWIN R. sTAUrrAcHER. y 

